TF阅读真题第817篇The Runaway Greenhouse Effect on Venus

The Birth of the Solar System                                     &nb...

The Greek City-States: Sparta and Athens Of the hundreds of city-states that evolved during the Archaic Age, (800- 479 B.C.), Sparta and Athens stand out for their vividly contras...

TF阅读真题第818篇Easter Island statues

The Origin of Mars's Moons     Mars has two tiny moons, Phobos and Deimos. The orbits of both these satellites are nearly circular and close to the planet: Phobos orbits...

TF阅读真题第835篇Sauropod Teeth and Nostrils

The Australlan Megatauna Extinctions Many of the species of large animals(megafauna) such as mammoths, mastodons, ground sloths, and giant deer that roamed the Earth tens of thous...

TF阅读真题第821篇Using Animal Bones to Determine Climates

TF阅读真题第847篇Waking Up Coming Out of Hibernation

TF阅读真题第809篇Animal Locomotion